Angular velocity sensor, electronic apparatus, and moving object

• US 9,599,469 B2
• Filed: 10/30/2014
• Issued: 03/21/2017
• Est. Priority Date: 10/31/2013
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Nishizawa, Ryuta, Kikuchi, Takayuki
• Primary Examiner(s): Patel, Harshad R
• Assistant Examiner(s): Shah, Samir M
• Application Number:
  US14/528,476
• Publication Number:
  US 20150114113A1
• Time in Patent Office: 873 Days
• US Class Current: 1/1
• CPC Class Codes: G01C 19/5607 using vibrating tuning forks double-ended tuning forks using planar vibrating masses suspended at opposite ends G01C19/5719
• CPC Class Codes: G01P 3/02 Devices characterised by the use of mechanical means

Abstract

In an angular velocity sensor, when a width of a detection frequency band is set to f1 [Hz], a resonance frequency in a first rotational vibration mode in which a base portion rotates and vibrates around a detection axis with respect to fixing units in association with the deformation of beam portions is set to f2 [Hz], a detuning frequency is set to f3 [Hz], and a resonance frequency in a second rotational vibration mode, having a phase opposite to that of the first rotational vibration mode, in which the base portion rotates and vibrates around the detection axis with respect to the fixing units in association with the deformation of the beam portions is set to f4, a relation of f1<f2<f3<f4 or a relation of f1<f2<f4<f3 is satisfied.

Claims

1. An angular velocity sensor comprising:

a fixing unit;

a base portion;

a supporting unit that supports the base portion with respect to the fixing unit;

a vibration unit that is connected to the base portion;

a detection unit that is connected to the base portion and vibrates by an action of a Coriolis force based on an angular velocity around a detection axis; and

a detection circuit electrically connected to the detection unit,

wherein a width of a detection frequency band of the detection circuit is f1 Hz,

a detuning frequency corresponding to a difference between a resonance frequency of the vibration unit and a resonance frequency of the detection unit is tuned to f3 Hz,

the supporting unit includes a plurality of beams each having a respective bending portion,

a resonance frequency in a first rotational vibration mode in which a mass constituted by the base portion, the vibration unit, and the detection unit, rotationally vibrates around the detection axis with respect to the fixing unit in association with deformation of the supporting unit is tuned to f2 Hz,

a resonance frequency in a second rotational vibration mode, having a phase opposite to that of the first rotational vibration mode, in which the mass constituted by the base portion, the vibration unit, and the detection unit rotationally vibrates around the detection axis with respect to the fixing unit in association with deformation of the supporting unit is tuned to f4 Hz, and

a relation of f1<

f2<

f3<

f4 or a relation of f1<

f2<

f4<

f3 is satisfied.

2. The angular velocity sensor according to claim 1,

wherein the first rotational vibration mode is a primary rotational vibration mode, and

wherein the second rotational vibration mode is a secondary rotational vibration mode.

3. The angular velocity sensor according to claim 2, wherein a relation of f1<

f2<

f3<

f4 is satisfied.

4. An electronic apparatus comprising the angular velocity sensor according to claim 3.

5. A moving object comprising the angular velocity sensor according to claim 3.

6. The angular velocity sensor according to claim 2, wherein a relation of 1.35≦

(f3/f2)≦

2.6 is satisfied.

7. An electronic apparatus comprising the angular velocity sensor according to claim 6.

8. A moving object comprising the angular velocity sensor according to claim 6.

9. The angular velocity sensor according to claim 2, wherein a Q value in the primary rotational vibration mode is equal to or greater than 5 and equal to or less than 100.

10. An electronic apparatus comprising the angular velocity sensor according to claim 9.

11. A moving object comprising the angular velocity sensor according to claim 9.

12. The angular velocity sensor according to claim 2, wherein a relation of (f1/f2)≦

0.5 is satisfied.

13. An electronic apparatus comprising the angular velocity sensor according to claim 12.

14. A moving object comprising the angular velocity sensor according to claim 12.

15. The angular velocity sensor according to claim 2, wherein a relation of 2≦

(f4/f2)≦

4 is satisfied.

16. An electronic apparatus comprising the angular velocity sensor according to claim 2.

17. A moving object comprising the angular velocity sensor according to claim 2.

18. An electronic apparatus comprising the angular velocity sensor according to claim 1.

19. A moving object comprising the angular velocity sensor according to claim 1.